Paul writes that the strong ought to bear with the failings of the weak and not to please themselves, for Christ did not please himself. Whatever was written in former days was written for our instruction, that through endurance and the encouragement of the Scriptures we might have hope. He prays that God grant them to live in harmony, so that together they may with one voice glorify the God and Father of our Lord Jesus Christ.
Therefore they are to welcome one another as Christ has welcomed them, for the glory of God. Christ became a servant to the circumcised to confirm the promises given to the patriarchs, and in order that the Gentiles might glorify God for his mercy. Paul quotes several Old Testament passages about Gentiles praising God and ends with a blessing: may the God of hope fill them with all joy and peace in believing, so that they may abound in hope by the power of the Holy Spirit.
From verse 14 Paul speaks of his ministry. He is a minister of Christ Jesus to the Gentiles, serving as a priest of the gospel so that the offering of the Gentiles may be acceptable, sanctified by the Holy Spirit. From Jerusalem as far as Illyricum he has fulfilled the ministry of the gospel, and he aims to preach where Christ has not been named, so as not to build on someone else's foundation.
That is why he had been hindered from coming to Rome. Now he hopes to see them on his way to Spain. First he must go to Jerusalem to bring aid to the poor among the saints, for Macedonia and Achaia were pleased to make a contribution. He asks the Romans to strive together with him in prayer that he may be delivered from the unbelievers in Judea and come to them with joy. He ends with a blessing: may the God of peace be with you all.